Probably not true - it is possible that you are entitled for more. For instance, because you two have one child, child support alone would be 17% of your combined income, which would equal close to what you are receiving now. That is without considering maintenance. However, more information is needed to provide a better answer, particularly whether or not he shows this amount is income (or if, for instance, he gets paid off the books, owns his own company, etc. all things which make proving income more complicated).
Also unclear is whether you two already have an existing agreement that both of you have signed accepting this amount. If you do, you would have to file for a modificaiton.
Either way, you should consult with a local matrimonial or family law attorney to aid you in this process - either find one on avvo.com or call the nassau county bar association. Because he is the monied spouse, he may also be responsible for paying for some or all of your attorney's fees.
Please note that my answer in no way establishes a lawyer/client relationship but is only meant to offer general advice. You should still consult with a local attorney regarding your legal matter.
Based upon the cap of $136,000 he is probably correct, ignoring add ons such as medical, child care, etc. which can really add up too. However, you have a good argument on spousal maintenance at first blush, and you should consult a matrimonial attorney about particulars and outcomes in your situation.
If you found this "helpful" or "best answer," please click it with my appreciation. My response is for educational purposes and does not constitute legal advice nor creates an attorney client relationship which requires all the details and a personal conference.
I agree with the other attorneys who answered. You need to have a lawyer assess the whole case and see if you can get maintenance. Further, you are entitled to your share of the marital assets (which may include a house, his pensions, and other items that a lawyer would need to review with you).